N = int(input())
line = input()

R_ = line.count("R")
W_ = line.count("W")

final_line = "R" * R_ + "W" * W_

dic = {"W":0, "R":0}

for idx, c in enumerate(line):
    if c != final_line[idx]:
        dic[c] += 1
        
print(max(dic.values())) N = int(input()) N int(input()) int input() input line = input() line input() input R_ = line.count("R") R_ line.count("R") line.count line count "R" W_ = line.count("W") W_ line.count("W") line.count line count "W" final_line = "R" * R_ + "W" * W_ final_line "R" * R_ + "W" * W_ "R" * R_ "R" R_ "W" * W_ "W" W_ dic = {"W":0, "R":0} dic {"W":0, "R":0} "W" "W" 0 "R" "R" 0 for idx, c in enumerate(line):
    if c != final_line[idx]:
        dic[c] += 1
         idx c enumerate(line) enumerate line if c != final_line[idx]:
        dic[c] += 1
         c != final_line[idx] c final_line[idx] final_line idx dic[c] += 1 dic[c] dic c 1 print(max(dic.values())) print max(dic.values()) max dic.values() dic.values dic values final_line = "R" * R_ + "W" * W_ "R" * R_ + "W" * W_ final_line dic = {"W":0, "R":0} {"W":0, "R":0} dic W_ = line.count("W") line.count("W") W_ R_ = line.count("R") line.count("R") R_ line = input() input() line N = int(input()) int(input()) N
N = int(input())
line = input()

R_ = line.count("R")
W_ = line.count("W")

final_line = "R" * R_ + "W" * W_

dic = {"W":0, "R":0}

for idx, c in enumerate(line):
    if c != final_line[idx]:
        dic[c] += 1
        
print(max(dic.values()))